nutrition and transport in flowering plants

• Veins carry water and mineral salts to the cells in the leaf blade and carry manufactured food from these cells to other parts of the plant
• The leaf blade has a large flat surface compared to its volume. This enables it to obtain the max amount of light for photosynthesis.
• A large, thin leaf blade also means that carbon dioxide can rapidly reach the inner cells of the leaf
• The leaf stalk holds the leaf blade away from the stem so that the blade can obtain sufficient light and air.
• The leaf blade has a upper epidermis made up of a single layer of closely packed cells. The upper epidermis is covered on the outside by a waxy and transparent cuticle.
• Beneath the mesophyll is the lower epidermis.
• The lower epidermis consists of a single layer of closely packed cells
• The cells are covered by an outer layer of cuticle , which reduces water loss through epidermis cells.
• The lower epidermis contains many minute openings called stomata
• Guard cells are found in the lower epidermis =.
• A pair of guard cells surrounds each stoma and helps to regulate the rate of transpiration be opening and closing the stoma.
• Guard cells contain chlorophyll which are not present in other epidermis cells.
• The mesophyll lies between the upper and lower epidermis.
• The mesophyll contains two kinds of tissues. Which are 1) Palisade Mesophyll and 2) Spongy Mesophyll
• The Palisade Mesophyll consists of one or two layers of closely packed, long and cyndrical cells
• Palisade Mesophyll contain numerous chloroplasts
• Palisade Mesophylls are specialised for photosynthesis
• Spongy Mesophyll contains cells with an irregular shape
• Spongy Mesophyll has numerous large intercellular sir spaces among the loosely packed cells
• The Spongy Mesophyll carries out photosynthesis but contains fewer chloroplasts than the palisade mesophyll
• Spongy Mesophyll have cells covered with a thin film of moisture
• Spongy Mesophyll contains transport tissue
• Spongy Mesophyll have the Xylem and Phloem which are grouped tgt to form a vascular bundle